NOZZLE DEVICE AND METHOD FOR ITS MANUFACTURE

Description

[0001] The invention relates to a nozzle device for drying and cleaning the edge region of a flat product, in particular a metal sheet or strip. Furthermore, the present invention also relates to a method for its production.

[0002] The dryness of flat products, especially metal sheets or strips, is an important quality criterion for their customers, especially when the end product is a cold-rolled flat product. Cold rolling typically involves the use of fluids that positively influence the rolling process; these can be emulsions or rolling oils, etc. These fluids must be removed from the surface of the flat product following the rolling process. This is traditionally done using a dry strip system, or DS system for short. The DS system uses a Coanda nozzle to non-contact seal the gap between the work roll and an upper deflector table, creating an airflow that surrounds the flat product and ensures that it is largely free of residual emulsion.However, due to the strong deflection of the air flow in the area of ​​the edges of the flat product, it may happen that residual emulsion drops are found in the edge area of ​​the flat product.

[0003] In order to effectively remove this residual emulsion from the flat product, various edge blow-off systems are used in the state of the art, in addition to the aforementioned DS system.

[0004] A first variant of the additional edge blow-off device is a zone-controlled edge blow-off system. Compressed air nozzles are located close to the roll gap to prevent emulsion from passing through the roll gap from the inlet to the outlet side of a rolling stand and wetting the edge of the flat product. As the name suggests, the blow-off nozzles can be switched on or off in different zones, depending on the width of the flat product.

[0005] In a second variant, the additional edge blow-off device essentially consists of compressed air nozzles that can be moved in the width direction of the flat product using an electric or pneumatic motor, thus allowing them to be adjusted to the current width of the flat product. Due to space constraints, however, this second variant can usually only be installed further back in the exit area of ​​a (cold) rolling stand for rolling the flat product.

[0006] The third variant of the additional edge blow-off device is a modification of the second variant. However, the third variant does not require a separate actuator for moving the edge blow-off device. Instead, the pressure nozzles are moved together with the side guide in the exit of a rolling stand.

[0007] Despite the additional edge blow-off device, problems still frequently occur in the edge area of ​​flat products. This occurs when the edge blow-off device either does not remove the residual emulsion from the edges in a process-stable manner, or when the emulsion is initially removed from the edge of the flat product but is subsequently deflected at another location in the exit area of ​​the rolling stand that rolled the flat product, rewetting the surface of the flat product. This leads to residual emulsion droplets on the surface of the flat product, which impairs its quality as the final product.

[0008] The aforementioned first variant of the switchable blow-off device, which can be switched on and off in individual zones, has the disadvantage that the blow nozzles cannot always be adjusted to the current strip width. However, there is insufficient space available for a movable variant in the area of ​​the roll stand gap. Depending on the width of the flat product, it may therefore happen that the compressed air nozzles of the additional edge blow-off device cannot apply sufficient force in the area of ​​the edge of the flat product, and the residual emulsion cannot therefore be optimally removed from the edge of the flat product.

[0009] Variants 2 and 3 attempt to address this problem by positioning the pressure nozzles based on the current width of the flat product. However, due to space constraints, these variants, which can be variably adjusted to the respective width of the flat product, can only be installed in the exit area of ​​a respective rolling stand for the flat product. This can lead to two adverse effects: 1.) The adhesion forces between the residual emulsion droplet and the surface of the flat product are too strong and prevent the blow-off process from detaching the droplet from the surface of the flat product. Instead, the compressed air nozzle transports the droplet of residual emulsion from the underside to the top side, or vice versa, leaving residual emulsion in the area of ​​the edge of the flat product. 2.) The residual emulsion droplets can be detaches from the edge of the flat product, but are not removed from there in a controlled manner. The detaches emulsion droplets bounce off other components in the run-out area of ​​the rolling stand and land back on the surface of the flat product. This effect is difficult to eliminate during the engineering phase, as the trajectory of the detaches emulsion droplets in the run-out area of ​​a rolling stand is influenced by various air currents, depending on, for example,the discharge speed of the flat product, the strength of the fume extraction and the strength of turbulence from rotating components, etc.

[0010] In the first variant of the switchable edge blow-off device, in which the blow-off takes place close to the roll gap of the rolling stand of the flat product, the effect 1) is not as pronounced, since there the DS system simultaneously generates an air flow away from the top side of the flat product.

[0011] From the German translation DE 692 10 835 T2 of the European patent specification EP 0 610 300 B1, a nozzle device according to the preamble of claim 1 is known. Specifically, this document discloses a device for removing moisture from an edge region of a metal strip. The device is C-shaped for passing the edge region of a strip through. The device includes nozzle assemblies in both an upper leg of the C-shaped housing and a lower leg of the C-shaped housing for discharging compressed air onto the lower and upper surfaces of the edge region of the strip to be dried, with the air being directed toward the edge of the strip to remove any moisture present on the strip.The C-shaped nozzle arrangement also contains an extraction pipe connected to a vacuum generation device for extracting the air from the edge area of ​​the strip to be dried. This air may contain moisture droplets blown off the surface of the strip by the nozzle arrangements. The device is housed in a housing. The housing can be moved toward or away from the strip or flat product by means of an electric motor.

[0012] A known possibility for the realization of a negative pressure generating device is in Figure 7in the form of a classic Venturi nozzle. To generate the negative pressure, compressed air is first introduced into ejector A. Due to the cross-sectional constriction of the driving nozzle, the so-called Venturi nozzle B, the introduced compressed air is accelerated. The dynamic pressure increases, while the static pressure in the air decreases. After passing through the driving nozzle, the accelerated air expands again, and a vacuum is created. Due to the vacuum, the air is "sucked" into the ejector through vacuum port D. The compressed air, together with the "sucked-in" air, exits the ejector through silencer C. The general advantages of using a Venturi nozzle are that these vacuum generators are particularly suitable for very high accelerations of the compressed air introduced into ejector A.

[0013] The Korean utility model KR 2010 0006932 U discloses a nozzle device in which a plurality of blow-off nozzles are arranged in a semicircle around an object to be sprayed or blown off.

[0014] US patent US 2,050,046 discloses a nozzle device for applying air or a liquid to the edges of a rolled stock in a roll gap. This effectively removes oil from these edges.

[0015] US patent application US 2019 / 0076856 A1 discloses a nozzle device according to the preamble of claim 1.

[0016] The invention is based on the object of developing a known nozzle device in such a way that the nozzle device is structurally simplified and designed in such a way that parts of the liquid blown off the flat product that are not sucked off cannot get outside the nozzle device.

[0017] This problem is solved by the subject matter of claim 1.

[0018] The nozzle device according to the invention has at least one suction device in which negative pressure is generated and which has at least one suction opening for sucking in and sucking out the liquid or the emulsion droplets blown off the edge of the flat product. The suction device with its at least one suction opening is also integrated into the nozzle device as part of the nozzle device through additive manufacturing, typically into the flank part. Preferably, the suction device with its suction opening, open toward the interior of the cavity spanned by the C-shaped nozzle device, is integrated into the flank part of the nozzle device in the form of a Venturi nozzle.

[0019] The term "oblique" in the present description does not mean perpendicular to the flat product, but at an acute angle with at least one component opposite to the direction of movement of the flat product relative to the nozzle device, and preferably also in the direction of the edge of the flat product.

[0020] The terms "integrated manufacturing", "additive manufacturing" and "3D printing" are used synonymously in this description.

[0021] The nozzle device is equally suitable for removing liquid, i.e., for drying and / or cleaning contaminants from the edge area of ​​the flat product. Any reference to drying or cleaning in the following is always only an example.

[0022] By simultaneously blowing off the liquid from the top and bottom of the flat product using the upper and lower blow-off nozzles, it is prevented, in particular, from migrating from the top to the bottom of the flat product due to adhesive forces, or vice versa. Instead, it is ensured that a liquid or emulsion droplet is reliably detached from the flat product at its edge. The combination of the claimed nozzle device with the aforementioned double-sided use of the upper and lower blow-off nozzles and preferably the dry-strip system known from the prior art advantageously ensures an optimally dry and clean strip surface.

[0023] The stressed flank part, by means of which the upper and lower legs are connected to one another, advantageously ensures that the cavity defined by the nozzle device is shielded from the surroundings of the nozzle device and thus ensures that emulsion drops detached from the surface of the flat product do not leave the nozzle device.

[0024] The claimed integral manufacturing of the nozzle, i.e. the additive manufacturing of the nozzle device by 3D printing, enables the integration of various components or functions within the nozzle device.

[0025] According to a first embodiment of the invention, integrated manufacturing allows all supply lines to the compressed air chambers and the upper and lower blow-off nozzles to be designed in such a way that a flow-optimized, uniform, and energy-saving flow is achieved for the first medium used to operate the primary nozzle and the second medium used to operate the at least one secondary nozzle. Furthermore, additive manufacturing can also be used to integrate additional pneumatic elements, such as throttles, valves, etc., into the 3D-printed nozzle device.

[0026] According to a third embodiment of the nozzle device, secondary nozzles are preferably formed adjacent to the primary nozzle on both sides, each of which discharges a secondary jet running parallel to the primary jet onto the surface of the flat product. The secondary jet serves to stabilize the primary jet and thus promotes effective drying or cleaning of the flat product.

[0027] Advantageously, in particular the secondary nozzles in the claimed nozzle device are designed in such a way that, together with an optimized outer contour of the respective leg in which the secondary nozzles are arranged, they utilize the Coanda effect and the outflowing media, in particular the outflowing compressed air, entrains ambient air in the vicinity of the respective leg, whereby the volume flow of the secondary jets is increased many times over and at the same time the energy requirement is reduced.

[0028] In principle, the primary nozzle and the secondary nozzles can be operated with a different first medium and a different second medium, respectively. However, the first medium and the second medium are preferably the same, and more preferably, they are both air.

[0029] As already explained above with reference to claim 1, the flank part serves to delimit the cavity defined by the nozzle device on one side. This advantageously prevents the air enriched with the liquid or contaminants from being released into the environment in an uncontrolled manner.

[0030] Preferably, the suction device, with its suction opening in the form of a Venturi nozzle opening towards the interior of the cavity spanned by the C-shaped nozzle device, is integrated into the flank part of the nozzle device. The suction openings are preferably located halfway between the upper and lower legs, more preferably in the direction of travel of the emulsion droplet detached from the edge of the flat product. The said design of the suction device as a Venturi nozzle causes negative pressure to develop at the suction openings, and in this way the first and / or second medium, i.e. preferably the air of the primary jet and the secondary jet, together with the detached emulsion droplet contained therein, is sucked in by the suction openings and transported away in a controlled manner in the suction device.

[0031] Thanks to the claimed combination of blow-off and suction in a single nozzle device, it is no longer necessary to locate the strip edge blow-off system as close as possible to the roll gap of an upstream rolling stand. This also frees up installation space in a technically critical area.

[0032] The large C-shaped design of the nozzle device shields the separation area, i.e., the space into which the liquid enters after being blown off the flat product, so that the liquid cannot escape outside the nozzle device. To ensure this even in the event that parts of the blown-off liquid are not captured by the negative pressure in the suction openings and removed by the suction device, a drain opening is arranged in the transition area between the flank section and the upper side of the lower leg.

[0033] In order to direct the liquid specifically to the drainage opening, the underside of the upper leg and / or the upper side of the lower leg are inclined towards the flank part, in particular towards the drainage opening. The inclination is designed in such a way that the liquid can flow due to gravity along the underside of the upper leg and / or the upper side of the lower leg towards the drainage opening. The provision of the inclination also prevents drops of liquid from accumulating on these surfaces within the cavity spanned by the nozzle device, which could otherwise drip or fall back onto the surface of the flat product.

[0034] Advantageously, the nozzle device according to the invention is positioned with the aid of actuators on the respective edges of the flat product to be cleaned. This allows for effective and energy-saving drying of the flat product.

[0035] To protect against damage, the nozzle device is advantageously housed in a metal cage.

[0036] The nozzle device according to the invention is preferably additively manufactured in one piece, i.e. manufactured using a 3D printing process. Alternatively, however, it is also possible to manufacture the nozzle device according to the invention in individual segments, which in turn are then each additively manufactured. This segmented design offers the advantage that in the event of any damage to the nozzle device, e.g. in the event of a crack in the flat product, only the defective segment needs to be replaced. It is also conceivable to design the part of the nozzle device that is typically located above the flat product to be cleaned in such a way that it is held in position by a safety coupling. In this case, the upper part of the nozzle device would be flexible in the event of a crack in the flat product and could then fold upwards and not suffer any major damage.

[0037] The nozzle device is preferably made of thermoplastic. This is a suitable material for the nozzle device for the following reasons: 1. It is significantly more cost-effective than using metal in 3D printing. 2. The plastic nozzle assembly is significantly lighter than a comparable 3D-printed metal nozzle assembly, simplifying assembly and allowing the actuators required for its positioning to be smaller and therefore more cost-effective. 3. Finally, metal parts subject to compressed air flow tend to develop condensation on their surfaces. This effect generally does not occur with plastic parts due to their lower thermal conductivity.

[0038] The description includes a total of 7 figures, of which Figure 1 shows a perspective view of the nozzle device according to the invention; Figure 2 shows a perspective longitudinal section through the nozzle device according to the invention; Figure 3 shows an enlarged detailed view of the primary nozzle and secondary nozzles according to Figure 2 Figure 4 shows the arrangement of the nozzle device according to the invention in operation with a flat product passing through; Figure 5 shows a cross-section through the nozzle device according to the invention; Figure 6 shows a cross-section through the flank part of the nozzle device with integrated suction device; and Figure 7 shows a Venturi nozzle according to the prior art. shows.

[0039] The invention will be described below with reference in particular to the Figures 1 to 6 described in detail. In all figures, identical technical elements are designated by identical reference numerals.

[0040] Figure 1shows the nozzle device according to the invention in a perspective view. The nozzle device 100 is C-shaped with an upper leg 110-o and a lower leg 110-u, both of which are connected to one another via a flank part 120 for passing through an edge region of a flat product 200 to be cleaned. In the transition region between the flank part 120 and the upper side of the lower leg 110-u, a drain opening 160 is formed for discharging residual liquid that was not captured and sucked away by a suction device 140, described later.

[0041] During operation of the nozzle device, the cavity 300 defined by the two legs 110-o and 110-u and the flank portion 120 is typically filled with air enriched with liquid droplets blown off the flat product. To prevent these liquid droplets in the air (aerosols) from accumulating on the underside of the upper leg 110-o and from there falling back onto the edge region of the flat product to be dried, the underside of the upper leg and / or the upper side of the lower leg are inclined toward the flank portion 120 and in particular toward the discharge opening 160.In order to produce the nozzle device in a structurally simplified and more efficient manner with its complex design and its diversely designed cavities, the present invention provides for the nozzle device 100 to be formed integrally with the two legs 100-o, 110-u, with the flank part 120 and with the two blow-off nozzles 130-o, 130-u by additive manufacturing.

[0042] Figure 2shows a longitudinal section through the nozzle device 100, wherein at least one upper blow-off nozzle 130-o is arranged in the upper leg 110-o, directed obliquely toward the upper side of the edge region of the flat product, for emitting a first blow-off jet 134, 137. The first blow-off jet serves to divert liquid collected on the upper side of the flat product toward the edge of the edge region of the flat product. Similarly, a lower blow-off nozzle 130-u is arranged in the lower leg 110-u of the nozzle device 100 and is directed obliquely toward the underside of the edge region of the compartment product to be dried. The lower blow-off nozzle 130-u serves to emit a second blow-off jet and to divert liquid located on the underside of the flat product to be dried with the second blow-off jet toward the edge of the edge region of the flat product 200.

[0043] In Figure 2Furthermore, three intake openings 142 are shown here as an example in Figure 2 The suction device 140, not shown in detail, can be seen. The suction device generates a negative pressure, which is present at the suction openings 142 for sucking in and sucking out the air in the cavity 300 with the liquid blown off the edge of the flat product. A more detailed description of the suction device 140 is given below with reference to the Figures 5 and 6 .

[0044] Figure 3First, the design of the upper blow-off nozzle 130-o is shown in detail. The lower blow-off nozzle 130-u in the lower leg 110-u is designed analogously. The upper or lower blow-off nozzle 130-o, 130-u is preferably also integrated into the nozzle device, specifically initially in the form of a primary nozzle 132, which is in fluid communication with a pressure chamber 133 integrated in the upper and / or lower leg. The primary nozzle 132 serves to discharge a primary jet 134, preferably at an acute angle onto the top or bottom of the flat product. The primary jet is formed from a first medium.

[0045] Also in the upper and / or lower blow-off nozzle, preferably on both sides adjacent to the primary nozzle 132, at least one secondary nozzle 136 is formed for emitting a secondary jet 137 running parallel to the primary jet 132, likewise preferably at an acute angle onto the surface of the flat product. The secondary jet 137 typically serves to stabilize the primary jet 134. The secondary jet is formed from a second medium, which may or may not be different from the first medium. Typically, the first and second media are the same and are typically air in both cases. The primary nozzle 132 and the secondary nozzles 137 are preferably each designed in the form of slot nozzles. In particular, if slot nozzles are formed, the primary nozzle and the secondary nozzle are arranged parallel to one another.

[0046] The primary jet and the typically two secondary jets adjacent on both sides together form the blow-off jet of the nozzle device 100. The secondary nozzles 136 are each in fluid communication with air intake openings 139 on the outside of the respective leg 110-o, 110-u via a channel 138 integrated in the respective leg 110-o, 110-u for sucking in ambient air to form the secondary jets 137. As already mentioned in the general part of the description, the outer contours of the legs 110-o, 110-u in the area of ​​the air intake openings 139 are each designed in such a way that the Coanda effect occurs in the area of ​​the air intake openings 139. As a result, ambient air is drawn into the channels 138 via the air intake openings 139, thereby increasing the effective volume flow of the secondary jets several times over and simultaneously reducing the energy required to generate the secondary jets. The Coanda effect, orThe suction of ambient air is further promoted in the secondary nozzles by the presence of tertiary nozzles 135, in that the tertiary nozzles also blow compressed air into the channels 138 of the secondary nozzles.

[0047] Figure 4 illustrates the operation of the nozzle device 100 according to the invention, in the left-hand illustration in a plan view and in the right-hand illustration in a cross-sectional view. In both illustrations, it can be seen that in each leg of the nozzle device 100, a plurality of blow-off nozzles 130-o are arranged parallel to one another. It can also be seen that the first or upper blow-off jets 134, 137 generated by them are directed with a first component against the direction of movement or against the direction of transport of the flat product to be dried and with a second component preferably simultaneously also towards the edge of the flat product. Also visible are the Figure 2 known suction openings 142 for sucking in and out the residual liquid blown off the edge of the flat product. As in Figure 2 and especially in Figure 4 As can be seen in the right-hand illustration, the suction openings 142 are arranged halfway between the upper and lower legs 110-o, 110-u, ie in the target area of ​​the blow-off jets after they have been diverted from the top and bottom of the flat product to be dried in a horizontal direction towards the flank part 120 of the nozzle device 100.

[0048] The Figures 5 and 6show the design of the suction device 140 according to the invention integrated into the flank part 120. The suction device is integrated in the form of a Venturi nozzle or a plurality of parallel Venturi nozzles, i.e., formed in the flank part 120 using a 3D printing process. Using the known principle of the Venturi nozzle, a negative pressure is generated at the suction openings 142 to suck in and remove the liquid blown off the edge of the flat product. The nozzle device according to the invention is made of plastic, preferably thermoplastic. List of reference symbols

[0049] 100Nozzle device 110-upper leg 110-lower leg 120Flank section 130-upper blow-off nozzle 130-lower blow-off nozzle 132Primary nozzle 133Integrated pressure chamber 134Primary jet 135Tertiary nozzle 136Secondary nozzle 137Secondary jet 138Integrated channel 139Air intake opening 140Suction device 142Suction opening 160Discharge opening 200Flat product 210Edge area of ​​the flat product to be cleaned 300Cavity spanned by the C-shaped nozzle device

Claims

1. Nozzle device (100) for drying and / or cleaning the edge region of a flat product (200), particularly a metallic sheet or strip, wherein the nozzle device is of C-shaped configuration with an upper and a lower limb (110-o, 110-u), the two of which are connected together by way of a flank part (120), for conducting the edge region (210), which is to be dried or cleaned, of the flat product through between the upper and lower limbs, further comprising: at least one upper blowing nozzle (130-o), which is arranged in the upper limb (110-o), for issuing a first blowing jet and at least one lower blowing nozzle (130-u), which is arranged in the lower limb (110-u), for issuing a second blowing jet, wherein the nozzle device (100) with the two limbs (110-o, 110-u), the flank part (120) and the two blowing nozzles (130-o, 130-u) are of integral construction in that they are additively manufactured; characterised in that the upper blowing nozzle (130-o) is directed obliquely onto the upper side of the edge region for conducting away liquid, which is present on the upper side, by the first blowing jet towards the edge of the edge region; the lower blowing nozzle (130-u) is directed obliquely onto the lower side of the edge region for conducting away liquid, which is present on the lower side, by the second blowing jet towards the edge of the edge region; at least one suction device (140), in which a sub-atmospheric pressure is generated, with at least one suction opening (142) for sucking up and sucking away the liquid blown off the edge of the flat product is provided; and the suction device (140) with the suction opening (142) is also integrated as part of the nozzle device (100) therein by additive manufacture.

2. Nozzle device (100) according to claim 1, characterised in that the upper and / or lower blowing nozzle (130-o, 130-u) respectively integrated in the nozzle device (100) is or are formed from: a primary nozzle (132), which is in fluid-conducting connection with a pressure chamber (133) integrated in the upper and / or lower limb, for discharge of a primary jet (134) of the blowing jet onto the upper side and / or lower side of the flat product (200), wherein the primary jet is formed from a first medium.

3. Nozzle device according to claim 2, characterised in that the upper and / or lower blowing nozzle (130-o, 130-u) each integrated in the nozzle device (100) further comprises or comprise: secondary nozzles (136), which are preferably formed on both sides adjacent to the primary nozzle (132), for respectively discharging a secondary jet (137), which extends parallel to the primary jet (134), of the blowing jet onto the upper side and / or lower side of the flat product (200) for stabilisation of the primary jet, wherein the secondary jet is formed from a second medium.

4. Nozzle device (100) according to claim 2 or 3, characterised in that the primary nozzle (132) and the secondary nozzles (137) are each configured in the form of slot nozzles.

5. Nozzle device (100) according to any one of claims 2 to 4, characterised in that the first medium and the second medium are the same and in that case are air, particularly compressed air.

6. Nozzle device (100) according to any one of claims 2 to 5, characterised in that the secondary nozzles (136) are in fluid-conducting connection by way of a channel (138), which is integrated in the respective limb (110-o, 110-u), with air suction openings (139) at the outer side of the respective limb in order to induct ambient air for formation of the secondary jets (137); and preferably at least one tertiary nozzle (135) for blowing compressed air into the channel (138) of the secondary nozzle (136) is associated with each nozzle (136).

7. Nozzle device (100) according to any one of the preceding claims, characterised in that the suction device (140) with the suction opening (142), which is open towards the interior of the cavity (300) spanned by the C-shaped nozzle device, is integrated in the form of a venturi nozzle in the flank part (120) of the nozzle device (100).

8. Nozzle device (100) according to claim 7, characterised in that the suction open (142) is formed in the flank part (120) to half height between the upper limb and lower limb (110-o, 110-u), preferably in the target region of the blowing jets (134, 137).

9. Nozzle device (100) according to any one of the preceding claims, characterised in that an outflow opening (160) for conducting away the liquid not picked up by the suction device (140) is formed in the transition region between the flank part (120) and the upper side of the lower limb (110-u).

10. Nozzle device (100) according to claim 9, characterised in that the lower side of the upper limb (110-o) and / or the upper side of the lower limb (110-u) is formed to be so inclined with respect to the flank part (120), particularly to the outflow opening (160), that the liquid can run away at the lower side and / or the upper side towards the flank part (120).

11. Nozzle device (100) according to any one of the preceding claims, characterised in that the nozzle device (100) with the two limbs (110-o, 110-u), the flank part (120) and the two blowing nozzles (130-o, 130-u) are formed integrally in that they are manufactured additively.

12. Nozzle device (100) according to any one of claims 1 to 10, characterised in that the nozzle device (100) can be assembled from a plurality of exchangeable segments, wherein the individual segments are each integrally additively manufactured.

13. Nozzle device (100) according to claim 12, characterised in that the upper limb (110-o), for example, as a segment of the nozzle device (100) is separately additively manufactured and is fastened, preferably movably, to the flank part (120) by a releasable coupling.

14. Nozzle device (100) according to any one of the preceding claims, characterised in that the nozzle device (100) is housed in a metal cage.

15. Nozzle device (100) according to any one of the preceding claims, characterised by an actuator for positioning the nozzle device (100) at the edge of the flat product.